Retired Army Lieutenant General and former National Security Advisor H.R. McMaster explains why military leaders need to study the past to gain clarity in the present and also shares a career worth of lessons to include why the Battle of 73 Easting taught him about the importance of tough, realistic training. Finally, he spends a few minutes talking about the mindset he adopted before he stepped into the role of the National Security Advisor and how he dealt with the stressors that came along with that position.